Thats right, it is a shielding wire. I believe orange is hot, white is the other end of the coil and black is the shield. But I'd advise checking that theory with a multimeter measuring resistance from orange to the other two. If you are doing a normal circuit, black and white would go together to ground. But if you are doing some clever series-type switching, do the switching with the white and orange, and still take the black to directly to ground.
The third wire, I do beleive is a green wire on the lace sensors is a pickup shielding wire, and in the quiting the beast shielding mod it should be connected on the same plane as the shielding so connect it to the back of the volume pot, should be just fine. Cheers.